1. Field of the Invention
The present invention relates to a rotating electrical machine that uses a stator coil obtained by curing the impregnating resin injected into an electrically insulated coil unit housed inside a slot via a slot liner.
2. Description of the Related Art
Rotating electrical machines such as the induction motor of railway cars, industrial induction motors, and generators have size and weight reduction requirements. One way to meet such demands is to improve the heat resistance of the insulation system adopted by the stator coil. During the operation of the stator coil, the temperature inside the slots surrounded by the iron core becomes higher than the temperatures of the coil end portion and the lead wire portion. Under these backgrounds, there is a need for a technique that can selectively improve the heat resistance of the insulation system inside the slots. For improved production efficiency and costs, the insulation system also requires a technique to improve heat resistance such as by using a general-purpose impregnating resin with a temperature tolerance class of 155 (which is defined in JIS (Japanese Industrial Standards) C 4003:2010) or less (insulation system with a temperature tolerance class of 180 (which is defined in JIS (Japanese Industrial Standards) C 4003:2010) or more). As an example, an insulation system is available that is configured from an impregnating resin, a mica tape, and a slot liner.